Fuse



E. w. snow.

FUSE; APPLICATION FILED AUG-HI I919.

Patented Apr. 12, 1921.

INVENTORI E77Z6$ h/Szzozzr 95 %zls ATTORNEY ERNEST W. SNOW, OF ROCHESTER, NEW YORK.

FUSE.

Application filed August 14, 1919.

To. all whom it may concern:

Be it known that I, Emvnsr W. Snow, a citizen of the United States, residing at Rochester, inthe county of Monroe and State of New York, have invented certain new and useful Improvements in Fuses; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference-numerals marked thereon.

My invention relates to fuses for the protection of electric circuits, or more particularly, to that class known as renewable cartridge fuses in which a new fusible strip or member may be inserted when desirable or necessary and has for its ob ect to provide a fuse which can be refilled or removed by an unskilled person without liability of mistake or of securing inadequate electrical contact. To this end the underlying feaure of the invention is the provision of a support or filler adapted to be received in a suitable tubular container, said filler being so fashioned that a flat strip of fusiblemetal such as zinc may be readily applied thereto and the filler inserted in a tubular holder of the ordinary or any preferred construction and eflicient electrical contact obtained directly with the ends of the fuse strip when secured in place;

The invention further consists in certain improvements in construction and COIIlblIlZL- tions of parts as w1ll be hereinafter de scribed, the novel features being pointed out in the claims atthe end of the specification.

In the accompanyingv drawings: Figure 1 1s. a longitudinal sectional view of the preferred form of the complete fuse ready for application to a holder of an approved form.

Fig. 2 isa perspective view of fuse support removed from its casing.

Fig. 3 is a view similar to Fig. 1 of a .modified form of fuse, and

Fig. at is a perspective view of the fuse supportremoved.

Fig. 5 is a cross sectional view on the line ma2 of Fig. 3. 1 i

Fig. 6 is aview'of a fusestrip detached.

Specification of Letters Patent. Patented Apr. 12, 1921.

Serial No. 317,525.

Similar reference characters in the several figures indicate similar parts.

Cartridge fuses of the type to which my invention relates, generally, embody a tubular casing of insulating material, such as vulcanized fiber or heavy pasteboard having at the ends thereof metallic caps or ferrules secured in positioneither permanently or removably and constituting the external contact members adapted to beheld by spring contact fingers on the fuse board or support and I have, therefore, shown my inventionapplied to a casing of this type, 1 indicating the tubular container of fiber or other similar material preferably threaded externally at its ends and provided with the end caps 2 screwed thereon and either or both of which may be removed. The filler or body member forming a part of my present invention is indicated by 3 and consists ofa rigid body of heat resisting insulating material such as asbestos lumber (made from asbestos fiber and cement) preferably of cylindrical form and slightly less in length than the inclosing casing. This body or carrier is provided with a narrow slot or groove extending lengthwise thereof, open at its narrower edge only, the ends of the slot at opposite ends of the filler being arranged on opposite sides of the axial center of the body, and there are provided one or more recesses 4i intermediate the length of the slot located at the points where it is desirable for the fuse to meltwhen the circuit is overloaded.

The fuse strip 5 is of Z shape composed of readily fusible metal, such as zinc, and is inserted edgewise in the slot in the filler, when removed from the container, theends being bent over as shownat 6 so that when the filleris in place within the container and the end caps or ferrules 2 screwed down tightly, the latter will make good mechanical and electrical contact with the ends of the strip and the filler is sufliciently rigid.

the axial center and the projecting ends of the strip are bent in opposite directions as shown, this arrangement also serving to hold the strips in place and preventing their dropping out during the insertion of the filler in the casing. If desired, the strip may also be secured in position by a cement composed of plaster of Paris or of some chemical substance which would either combine with the fuse when melted or merely serve to hold it in position, or the strip could be secured by a cover or wrapping of asbestos paper or similar insulating material.

It will be noted that by making the slot.

in the filler narrow and inserting the fuse strip edgewise only a very narrow portion of the metal is adjacent the tubular container 1 so that when the fuse is melted by overload or short circuit, there is little or no liability of burning or charring the containerand at the same time the intermediate recess or recesses a will afford an escape for the gases.

In Figs. 3, 4: and 5 I have shown another embodiment of my invention in which the filler 6 is provided with a hollow cylindrical portion 7 preferably at the center which s provided on one side only with a longitudlnally extending slot 8 and the opposite sides of the ends are cut away to form inclined supports 9 for the fuse strip extending from the ends of the part 7 to the extreme ends of the filler on diametrically opposite sides of the latter. The fuse strips 10 for use with this form of filler are preferably reduced in diameter at the center as at 11 so thatv they will extend through the hollow portion 7 without contacting therewith, in order that when they are blown at this point by short circuit or overload the container or casing will not be damaged or burned. The wider portions of the fuse strip rest upon the inclined supports 9 on the filler and the extreme ends are bent over the ends of the filler in opposite directions as shown, where they may be'engaged by the end caps or ferrules on the container when secured in place. In applying this form of fuse it is only necessary, as before, to insert it edgewise in the slot and bend the ends over, which may be readily accomplished by an unskilled person.

By arranging the fuse strip edgewise in a'narrow slot in the filler and bending the ends toward and across the ends from opposite sides of said ends the strips may be more readily applied to the filler and inserted in the container without liability of becoming displaced and the ends of the strips are also of sufficient size to make good contact and prevent breakage or displacement when the caps are screwed in place.

I claim as my invention:

1. A support for a renewable fuse strip and adapted for insertion in an inclosing casing, comprising a body of rigid insulating material having surfaces in the same plane on its outer ends and adapted to support the laterally projecting ends of a fuse strip on said surfaces and provided with a recess between said ends through which the strip extends out of contact with the body.

2. A support for carrying a fuse strlp comprising a body of rigid insulating material having a narrow, deep slot open at its outer edge and extending longitudinally thereof, the ends of the slot at the extreme ends of the support being arranged on opposite sides of the axial center of the body.

8. A fuse support composed of a rigid body of insulating material having a narrow longitudinally extending slot therein and a recess intermediate its ends in combination with a fuse strip inserted edgewise in. said slot and having its ends extended over the ends of the body in opposite directions.

4. In a fuse, a tubular container of insulating material having threaded ends and metallic end caps mounted thereon, in combination with a rigid fuse holding support of insulating material removably arranged within the container and provided with a narrow longitudinal slot and with its Wider lateral dimension extending substantially diametrically of the same and a flat removable fuse strip arranged in said slot and having its ends bent over the ends of the support and adapted to be engaged by the end caps of the container.

5. In a fuse comprising a tubular container having threaded ends and end caps mounted thereon, a removable rigid fuse holding support within the container composed of insulating material havinganarrow slot extending longitudinally the full length thereof the wider lateral dimension of the slot extending substantially diametrically across the support and a fuse link of wide and thin metal arranged in the slot and having its ends extending laterally over the outer ends of the support in opposite directions and adapted to be engaged by the con: tainer caps. v V

6. A fuse comprising a tubular container having removable metallic contact caps at the ends, a removable rigid fuse holding support of insulating material within the container having a narrow slot extending longitudinally thereof and a'recess intermediate its ends and a removable fuse strip of thin metal located in said slot, extending across the recess and having its extremities extending laterally across the ends of the support and adapted to be engagedby the caps on the container.

7. A Z shaped fuse strip inserted edgewise in a cylindrical insulating member, adapted to be contained in a cartridge fuse, the parallel end portions of the fuse strip abutting against the ends of the cylindrical insulating member.

8. In a refillable fuse the combination with an insulating tube of end caps secured thereto, an insulating support for a fuse strip Within said tube extending from end to end thereof and provided with a slot of greater Width and depth than the fuse strip, and a fuse Within the slot of said support, 10 the ends of said fuse being turned down and in cooperation throughout the Width and length of the turned down ends With the inner faces of said end caps.

ERNEST W. MSNOW. 

